Best inverter for the buck

[Ron20324]

... I'm always inclined to go with the simplest, most effective and cheapest solution. ...Pete

If you have two spare AC breaker positions: On my AC panel, the top 2 breakers are shore power. The 3rd is the battery charger. The 4th and 5th are the outputs from the inverter. There is a slide lockout which serves double-duty: To switch to EITHER the shore power OR inverter, plus if on inverter, the battery charger breaker can not be turned on. The cost is 2 circuit breakers and some wiring of the breaker panel.

 

[Ron20324]

... My boat has a breaker for each outlet.

So, that would be 15 (or 20?) amps per outlet, times how many outlets? On a 30-amp shore power breaker, Or perhaps you have 50 amps?

 

[prroots]

If you have two spare AC breaker positions: On my AC panel, the top 2 breakers are shore power. The 3rd is the battery charger. The 4th and 5th are the outputs from the inverter. There is a slide lockout which serves double-duty: To switch to EITHER the shore power OR inverter, plus if on inverter, the battery charger breaker can not be turned on. The cost is 2 circuit breakers and some wiring of the breaker panel.

Thanks. On my panel the first two are shore power, followed by battery charger, water heater, and finally AC outlets. There are no spares. I'm guessing your inverter was a factory option and they provided a compatible panel. My boat has never had an inverter.
Pete

 

[prroots]

So, that would be 15 (or 20?) amps per outlet, times how many outlets? On a 30-amp shore power breaker, Or perhaps you have 50 amps?

Yes, we have many outlets on a single 15 or 20 Amp circuit breaker with 30 Amps total coming into the boat. If I recall correctly, our last two sailboats were the same way.
Pete
PS we are always tripping the breaker whenever we try to run the space heater and anything else simultaneously!

 

[Ron20324]

I'm guessing your inverter was a factory option and they provided a compatible panel. Pete

I installed a larger breaker panel myself, had to change the breaker panel to get the 2 more postions. When my B323 was new, the first time we tried to run the heater and a coffee pot (shore power), the 15 breaker popped. I looked into the panel and found though they had wired the 6 AC outlets with 2 cables, they put both on the same breaker- limiting me to 15 amps of the 30 amps. I added another breaker and moved one of the wires, and now all is dandy.

 

[mitiempo]

So, that would be 15 (or 20?) amps per outlet, times how many outlets? On a 30-amp shore power breaker, Or perhaps you have 50 amps?

4 outlets - 15 amp rated each. 30 amp shorepower. The problem of breakers overloading described above by prroots is one I don't have. I only have to concern myself with the total amp load on the shorepower cord and my ammeter lets me know the total loading any time I glance at it. Right now I have 2 heaters on, 1 low and 1 medium as well as a 10 amp battery charger and I am using 18 amps. With only 1 breaker for outlets the heaters would trip it if they were on the same circuit.

Most boats have 30 amp service and even one of the smaller Blue Seas panels (8099) comes with a 30 amp main and 4-15 amp breakers installed. I have the 8027 with 30 amp main and 6 - 15 amp breakers.

 

[prroots]

After reviewing numerous inverters online and seeing the feedback from this forum, I have come to some general conclusions:

1. Prefer the pure sine wave version to guard against equipment damage, poor equipment operation, and RF noise
2. The transfer switch versions are undesirable since I don't want to drain down batteries if for any reason shore power lost eg, during night or while unattended ie, all critical equipment runs directly off 12 VDC anyways.
3. The standalone version should work fine if wired through a DPDT switch off AC outlet breaker such that all AC outlets are fed from either shore power or inverter but never both simultaneously. This also guards against feeding water heater or battery charger from inverter.

Comments appreciated.
Pete

 

[prroots]

I've discovered that Cotex, distributed by Samlex in the US, makes a wide variety of 1500 watt pure sine wave inverters such as:
SSW-1500-12A for $354
PST-150S-12A for $413
SA-1500-112 for $476
S1500-112 for $545
SK1500-112 for $599

Has anyone experience with this brand?
Pete

 

[Stu Jackson]

After reviewing numerous inverters online and seeing the feedback from this forum, I have come to some general conclusions:

1. Prefer the pure sine wave version to guard against equipment damage, poor equipment operation, and RF noise
2. The transfer switch versions are undesirable since I don't want to drain down batteries if for any reason shore power lost eg, during night or while unattended ie, all critical equipment runs directly off 12 VDC anyways.
3. The standalone version should work fine if wired through a DPDT switch off AC outlet breaker such that all AC outlets are fed from either shore power or inverter but never both simultaneously. This also guards against feeding water heater or battery charger from inverter.

Comments appreciated.

Pete

1. My personal experience is that a pure sine wave is not required. We run our microwave with our Freedom 15 circa 1998 modified sine wave just fine, 1500 watt inverter built in to the Freedom combined inverter/charger, and the laptop and all other chargers on board, like for rechargeable batteries, work just fine.

2. Our Freedom 15 has an ATS. All I have to do is make sure the hot water heater is OFF. This is a simple management issue, since it is OFF all of the time anyway. I only turn it on for 15 minutes at a time for heating hot water anyway when plugged into shorepower. Many folks incorrectly leave them on all the time unnecessarily.

3. Since our charger is part of our Freedom 15 it has a separate switch on our Link 2000 to start the charger. I don't have that issue, but yes, you're right, for those with chargers separate from their inverters, they need to manage their systems so that they don't have their chargers on when the inverter is running.

Your boat, your choice, but I keep hearing you say DPDT switch. I would caution you to use the Blue Sea 8032 transfer switch or an equivalent rather than a simple DPDT. Maybe I'm overreacting.

 

[prroots]

Pete

1. My personal experience is that a pure sine wave is not required. We run our microwave with our Freedom 15 circa 1998 modified sine wave just fine, 1500 watt inverter built in to the Freedom combined inverter/charger, and the laptop and all other chargers on board, like for rechargeable batteries, work just fine.

2. Our Freedom 15 has an ATS. All I have to do is make sure the hot water heater is OFF. This is a simple management issue, since it is OFF all of the time anyway. I only turn it on for 15 minutes at a time for heating hot water anyway when plugged into shorepower. Many folks incorrectly leave them on all the time unnecessarily.

3. Since our charger is part of our Freedom 15 it has a separate switch on our Link 2000 to start the charger. I don't have that issue, but yes, you're right, for those with chargers separate from their inverters, they need to manage their systems so that they don't have their chargers on when the inverter is running.

Your boat, your choice, but I keep hearing you say DPDT switch. I would caution you to use the Blue Sea 8032 transfer switch or an equivalent rather than a simple DPDT. Maybe I'm overreacting.

Thanks. I'm a believer in the KISS principle and DPDT embodies that. Why buy something far more complicated, expensive, and less effective when a simple fool-proof solution is available? With the DPDT solution I don't have to manage the hot water heater or battery charger and I don't have to make available the space for an unnecessary panel (which I don't have). I have yet to hear any reason why the DPDT would not be the superior solution given function, cost, and space utilization. Yes, I admit the 8032 would look far more sophisticated and maybe add to the resale value

As far as pure sine wave goes, I'm a bit concerned about my printer so I'd rather be safe than sorry. Also, there are reports that modified sine wave can create problems with TV displays (even though we have yet to install a TV). Since the pure sine wave inverters are readily available at reasonable cost, why not take advantage?
Pete

 

[Stu Jackson]

Pete, yeah, much of what you say is answered by my "Your boat, your choice." Do you by any chance have a link to the DPDT switch you intend to use? Just askin'...

 

[mitiempo]

Thanks. I'm a believer in the KISS principle and DPDT embodies that. Why buy something far more complicated, expensive, and less effective when a simple fool-proof solution is available? With the DPDT solution I don't have to manage the hot water heater or battery charger and I don't have to make available the space for an unnecessary panel (which I don't have). I have yet to hear any reason why the DPDT would not be the superior solution given function, cost, and space utilization. Yes, I admit the 8032 would look far more sophisticated and maybe add to the resale value

As far as pure sine wave goes, I'm a bit concerned about my printer so I'd rather be safe than sorry. Also, there are reports that modified sine wave can create problems with TV displays (even though we have yet to install a TV). Since the pure sine wave inverters are readily available at reasonable cost, why not take advantage?
Pete

You still need a breaker which your DPDT switch isn't.

I agree with Stu - modified sine wave is fine - for your microwave, printer, and tv. A quality modified sine wave unit will be a better choice than a no-name rebranded sine wave inverter like you are looking at.

Microwaves like lots of amps on start-up. Look at the back of your microwave and double the watt rating for good results - on start-up they require more than they are rated for, which a shoreside system provides for the split second necessary.

A good choice would be the Magnum in the 2000 watt size http://www.magnumenergy.com/Products/MEseries.htm

It is a better inverter than a Xantrex and much better than what you are looking at.

 

[prroots]

You still need a breaker which your DPDT switch isn't.

I agree with Stu - modified sine wave is fine - for your microwave, printer, and tv. A quality modified sine wave unit will be a better choice than a no-name rebranded sine wave inverter like you are looking at.

Microwaves like lots of amps on start-up. Look at the back of your microwave and double the watt rating for good results - on start-up they require more than they are rated for, which a shoreside system provides for the split second necessary.

A good choice would be the Magnum in the 2000 watt size http://www.magnumenergy.com/Products/MEseries.htm

It is a better inverter than a Xantrex and much better than what you are looking at.

Thanks. That appears to be an inverter/charger combo with transfer switch. I'm looking for an inverter without transfer switch for my application. I did look for their inverters and could only find the MM612 inverter which is just 600 watts and includes a transfer switch. Seems a very limited selection.

As far as microwave power is concerned, the front says 800 Watts, but multiplying the amps times volts gives 1260. I hope to purchase a 1500 watt inverter with 3000 watts surge rating. I'm thinking that will do the job.

Anyone have any 1500 watt standalone (ie, without charger or transfer switch) inverters they can recommend?
Pete

 

[Ron20324]

I'm looking for an inverter without transfer switch for my application. As far as microwave power is concerned, the front says 800 Watts, Pete

Of course you don't HAVE TO connect the shore power to the inverter- so it will not be a switching unit- just a straight inverter like you want. My Xantrex is that way, so I did not wire the shore power that way, something you may want to consider. The micro's 800 watts is the cooking power, not electrical consumption. All micros are rated that way, and efficiency will dictate if one unit uses more input power than another of the same rating.

 

[prroots]

Pete, yeah, much of what you say is answered by my "Your boat, your choice." Do you by any chance have a link to the DPDT switch you intend to use? Just askin'...

Actually, I just learned from another forum that I should also switch grounds as well as hot and neutral. This means I would be looking for a 3PDT not a DPDT. I haven't confirmed it yet, but believe that the safety ground on the outlets is supplied from shore power. The idea of the 3PDT switch is to switch safety ground from shore to ship's ground when switching from the shore to the inverter position. Here's an example:
http://www.zorotools.com/g/00057631/k-G1021535/
Pete

 

[prroots]

Of course you don't HAVE TO connect the shore power to the inverter- so it will not be a switching unit- just a straight inverter like you want. My Xantrex is that way, so I did not wire the shore power that way, something you may want to consider. The micro's 800 watts is the cooking power, not electrical consumption. All micros are rated that way, and efficiency will dictate if one unit uses more input power than another of the same rating.

Right, the power listed on the front is the RF power supplied for cooking. The rear panel listing is the power consumed to produce the RF power. I don't understand how you wired your Xantrex. Are you saying it had a transfer switch, but you don't utilize it?
Pete

 

[Ron20324]

corrected grounding info.

I don't understand how you wired your Xantrex. Are you saying it had a transfer switch, but you don't utilize it?
Pete

I could be wrong, but I'd think almost any decent inverter would have the transfer function- but you wouldn't use it that way. I just did not wire the shore power to the inverter.

Think about it: IF you did wire in the s.p., and it cuts off, the inverter puts out. If there is never any s.p., then the inverter is always working, as in it's "static" mode (if the "on" switch is on). Leave the s.p. wired to wherever it is now (or through whatever switch you install.)

You DO DO DO want to switch the ground wire. I dug out Calder's book for further reading, and he goes into further detail: In the case where you have shore power NOT wired through the inverter transfer switch, if the inverter is on, the inverter's neutral and ground are connected, but opens if there is AC shore power into the unit or the inv turned off. With a DPDT switch only, the shore power ground would be connected to the inverter's ground and thus the inverter's neutral. NOT GOOD. IF IF IF the inverter is never on when shore power is on, then shouldn't be a problem?
See Calder's 3rd edition, p 264.

 

[prroots]

I could be wrong, but I'd think almost any decent inverter would have the transfer function- but you wouldn't use it that way. I just did not wire the shore power to the inverter.

Think about it: IF you did wire in the s.p., and it cuts off, the inverter puts out. If there is never any s.p., then the inverter is always working, as in it's "static" mode (if the "on" switch is on). Leave the s.p. wired to wherever it is now (or through whatever switch you install.)

You do not want to switch the ground wire. All AC grounds should be interconnected and not interuppted by a circuit breaker or switch. SAFETY FIRST!

Thanks. I would say that the majority of inverters are standalone (ie, without transfer switch). These tend to be less expensive and, therefore, preferred. Our use of the inverter is for occasional use and it will only be turned on when actively using it. A remote switch will be very handy. I can't speak to the quality or reliability, but this inverter looks very nice (on paper at least):
http://www.samlexamerica.com/customer_support/pdf/SlickSheets/SSW-1500-12A_Samlex_Specifications.pdf
and the price looks good as well:
http://www.batterystuff.com/batteries/ssw-1500-12a.html
Pete

 

[Benny17441]

Pete when figuring on the cost of an inverter installation you have to figure in the 12V leads, a 100 AMP fuse and an On/Off switch. So you may want to add $75 to your budget. A 1500 watt Xantrex unit retails for around $125 so you may be looking at $200. Make sure you get a unit where the fan only operates when there is a load as it will cut down in power usage and noise. The unit should be installed in a dry and well ventilated place but as close to the batteries as possible. It is possible to use gauge 4 wires if you maintain proximity to the batteries but if you are forced to extend the distance then thicker gauges will be required addying to the expense. 120V handles longer wire runs much better than 12V so it is more practical to install the unit closer to the batteries and then run an extension cord to the 120V appliance. This units are recommended for stand alone use and as such come equped with 2 or 3 outlets. I would not try to hard wire one into the boat's AC circuits as the cost of doing so would defeat the purpose of installing an inexpensive inverter. With a 25' extension cord you could provide power to any place in the boat and better be able to manage your loads. If your microwave oven is hard to access I can see that this would be a problem but it all depends how bad and how often would you like to use it. These Xantrex units provide clean enough power to operate TVs, VCRs, MW ovens, lamps, refrigerators, fans and others. I can't urge you enough, if you do decide to install one of these units, to get a Fuse Block with a 100 Amp fuse and an on/off switch sou you will not need to rely on the perhaps cheap switch on the inverter when the boat is unattended.

 

[prroots]

Pete when figuring on the cost of an inverter installation you have to figure in the 12V leads, a 100 AMP fuse and an On/Off switch. So you may want to add $75 to your budget. A 1500 watt Xantrex unit retails for around $125 so you may be looking at $200. Make sure you get a unit where the fan only operates when there is a load as it will cut down in power usage and noise. The unit should be installed in a dry and well ventilated place but as close to the batteries as possible. It is possible to use gauge 4 wires if you maintain proximity to the batteries but if you are forced to extend the distance then thicker gauges will be required addying to the expense. 120V handles longer wire runs much better than 12V so it is more practical to install the unit closer to the batteries and then run an extension cord to the 120V appliance. This units are recommended for stand alone use and as such come equped with 2 or 3 outlets. I would not try to hard wire one into the boat's AC circuits as the cost of doing so would defeat the purpose of installing an inexpensive inverter. With a 25' extension cord you could provide power to any place in the boat and better be able to manage your loads. If your microwave oven is hard to access I can see that this would be a problem but it all depends how bad and how often would you like to use it. These Xantrex units provide clean enough power to operate TVs, VCRs, MW ovens, lamps, refrigerators, fans and others. I can't urge you enough, if you do decide to install one of these units, to get a Fuse Block with a 100 Amp fuse and an on/off switch sou you will not need to rely on the perhaps cheap switch on the inverter when the boat is unattended.

Thanks; good advice. I do, however, think the hard-wiring of standalone inverter into existing AC outlets will be well worth the effort and expense via a 3PDT switch. Also, everything I read online suggests that pure sine wave inverters are much superior, in several respects, to the modified sine wave inverters.
Pete